What this means
People who had part of a knee or hip replaced walked more each day than those who had a full replacement. This study watched activity with wrist devices, so it shows links, not proof that the surgery caused the difference.
Plain-English summary written by an AI model from the abstract. The original is below.
- Who it was tested in
- 2,283 adults aged 40 to 69 from the UK Biobank
- Kind of research
- A study
The science
- Original title
- Accelerometry-based comparison of functional outcomes across total and partial knee and hip arthroplasty : a propensity-matched UK Biobank Study.
- Authors
- Glynou SP, Musbahi O, Sousi S et al.
- Journal
- Bone & joint research
- Published
- Oct 13, 2026
- Study type
- Study
- PMID
- 42866923 ↗
Abstract
Background
To evaluate objectively measured physical activity after hip and knee arthroplasty using accelerometry, by comparing bone-preserving procedures with total athorpalsties rthorpalsties and benchmarking both against non-arthritic controls.
What they did
This observational study was conducted within the UK Biobank. Adults aged 40 to 69 years with total knee arthroplasty (TKA), unicompartmental knee arthroplasty (UKA), total hip arthroplasty (THA), or hip resurfacing (HR) were identified through linked hospital records and completed seven-day wrist-worn accelerometry (Axivity AX3). Outcomes included adjusted daily step count (primary), peak cadence, moderate-to-vigorous physical activity (MVPA), and Euclidean Norm Minus One (ENMO). Surgical groups were propensity score-matched to non-arthritic controls on demographics, lifestyle factors, and comorbidities. Direct comparisons between procedure types were examined using both propensity-matched analyses and complementary multivariable regression, and adjusted for demographic and clinical covariates. Subgroup analyses considered < 12 months and ≥12 months post-surgery.
What they found
A total of 2,283 participants were included (TKA = 860, UKA = 162, THA = 1,168, HR = 93). Compared with matched controls, TKA and THA patients showed persistently lower activity, while UKA and HR achieved levels similar to controls. In the knee cohort, UKA patients walked significantly more steps/day than TKA (9,150 vs 7,920; + 15.5%, p < 0.001) with higher cadence. In the hip cohort, HR patients outperformed THA (10,122 vs 9,139 steps/day; + 10.6%, p = 0.032) and demonstrated higher peak cadence, and HR remained comparable to controls. All groups fell within the 'somewhat active' to 'active' step-count range (7,500 to 12,499 steps/day). UKA and HR are associated with higher postoperative activity compared with total arthroplasty (TKA, THA). Accelerometry provides an objective, scalable assessment of functional recovery, highlighting procedure-specific differences that should be considered alongside implant longevity when selecting surgical options.
The authors' abstract, grouped under plain headings from its own section labels.
Glynou SP, Musbahi O, Sousi S et al. Accelerometry-based comparison of functional outcomes across total and partial knee and hip arthroplasty : a propensity-matched UK Biobank Study. Bone & joint research. 2026. doi:10.1302/2046-3758.1510.BJR-2025-0603.R1. PMID: 42866923. https://pubmed.ncbi.nlm.nih.gov/42866923/